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String theory - if you need 10 dimensions to make the math work, it is right off the bat delusional as Penrose said. Quantum field theory - if you need infinities to make predictions right, it's more delusional than string theory.
Maybe the “Tube Hypothesis” could further string theory and possibly quantum field theory? - tube hypothesis proposes that the fundamental strings in string theory are tubes (possibly two-dimensional) that facilitate vibration, by channeling the flow of spacetime.
@harper262 what you are saying is exactly the problem physicists are trying to resolve. General Relativity says gravity is warping of spacetime due to mass-energy. QFT says fundamental forces, of which gravity is one, is mediated through particles. We need a new theory to reconcile the two descriptions.
But QFT says nothing about gravity. That's the problem. Gravity isn't a force but can be described in terms of gauge fields. In QFT gauge fields correspond to force carriers and so gravity is assumed to be a force. However, there is no trivial way to quantize gravity and that's where the problem lies - providing a quantized field-theoretic description of gravity @@Johnny-bm7ry.
That’s not what the issue is. You can write down a perfectly good theory of quantum gravity in 2 dimensions, so whatever intuitions we have about general relativity aren’t really a problem. The problem is that quantized general relativity in 4 dimensions is nonrenormalizable. You need to include an infinite number of free parameters to get results that aren’t obviously unphysical infinities. This is a huge problem and physicists really don’t like it.
Exploring theories, even when they eventually don't give us all answers, is never a waste. It enriches our knowledge and often points us in a new direction.
Check your local paper, or online, for the next Single Sock Symposium (SX3) in your area. The best place to find that matching single sock you've been looking for that you lost through the dryer wormhole.
Since your dryer lives in a symmetrical spacetime-system (see Noether theorem), eradication of your socks would violate conservation of energy (aka mass). There are three things, that hold in symmetrical systems - otherwise our universe would collapse: i) conservation of energy, ii) conservation of momentum, iii) Pauli's exclusion principle. Every single known physical law obeys these basic principles.
I have an idea on how to visualize string theory's extra dimensions. As it's been said that it's impossible for our brains to visualize extra dimensions, this can bypassed by the assertion that the extra dimensions are compactified, so the visualization can remain 3D. Each of the extra compactified dimensions can be visualized by giving an object extra visual properties but keeping their 3D location the same. Imagine a ball. You can visualize it moving through the first 4 dimensions by moving it around and watching it in motion. Then imagine a 5th dimension: moving through a color gradient from blue to red. So now you can move a ball through regular 4D space (its motion being the 4th dimension), and you can move it back and forth through the 5th by changing its color from red to blue or back. You can then add additional visual properties to represent further dimensions. Imagine a conversation between 2 particles: "Hey, I'm here where you told us to meet, at the exact coordinates and at the right time, but I don't see you", "Your x,y,z is correct, and I'm still here. However, you need to come bluer to me. You're too far away off in the red. Come bluer and you'll see me" "Oh ok, I see you now. I must've taken the wrong turn at purple". If you take away an object's innate visual description and give it to the coordinate system, you can represent another dimension by having it represent another dimension's gradient by making it be an arrow that can point in various directions, each direction representing a point on that dimension's gradient. Like an arrow on a speedometer pointing to numbers, it could be pointing at its representive coordinate for that dimension. So if the 6th dimension were represented by a fuel fage, those particles can extend their conversation: "let's go for a stroll. We can keep our x,y,z coordinates, stay in the blue, but we can take a stroll from full to empty and then back. 1 lap". Since motion in the extra dimensions doesn't affect the x,y,z coordinates, this should work, as it remains conistent with the 3D world, borrowing some of its attributes to represent motion in dimensions we can't see, the same way that worldlines on a spacetime diagram borrow the Y dimension to represent time.
U r the first one to have a similar idea as mine.. Honestly I don't like this.. I thought that was an original idea of mine which only I thought of.. Feeling odd to see someone with similar thought process.. My idea was just the same.. It's like we all are living in red 3D space with yellow and other colours 3D space overlaying ours.. . Imagine we living inside a Rubik's cube with each face colour emitting that color light and we living in red 3D face.. All 6 sides emitting thier colour .. They are the other dimensions we can't access coz we are not just colour blind in our eyes but colour blind in our bodies as a whole.. And some higher being who is not colour blind can see us all 6 coloured beings with his eyes... Just like we can see video games character but they can't see us or know of us..
@@godspeed5428 I have also considered the possibility that qualities associated with sensory experience could be considered as dimensions and formalized mathematically. Though I hadn't considered it in nearly so much depth as OP. It would certainly jive with the idea that consciousness plays some role in physics.
A little late to the party but at 11:14 i like the birth date and date of death for each forefather of mathematics and science being exactly true to fact. That's why I like arvinash
Don't worry, you haven't been missing much. String Theory has nothing to do with reality and everything to do with the University system collecting billions of dollars in tuition $$$ from physics students. I can't imagine how cognitively compromised I would have to be before I would agree to pay an institution that much $$$ for a degree in science fiction.
I remember taking calculus in college. We were assigned the problem of rotating the y=1/x function around the x-axis to form a cone. Then calculate both the volume and surface area of the cone from x=1 to infinity. The result was a cone with a finite volume, but an infinite surface area. In other words, you could fill it with paint, but couldn't paint the inside. My point : Just because the math says something .... doesn't mean it reflects reality.
Math can reflect reality, as you say, to a very high degree. One might even say it's unreasonable effective at it. 😏 Just never try to work infinity into those equations. 😂
Until you define what you mean by 'Reality', you can't say whether math is an accurate description of it or not. If your definition of reality includes the role of the (human) observer, then you have to use math to describe consciousness....good luck with that ...
...and I thought before I stopped using my DDCs, like Blender to make computer graphics, that was hard... ua-cam.com/video/w0bnigQ17JE/v-deo.html What's the point now that Sora and stuff like that does the same thing with a few prompts.
@@portugalforme1198 Whoa, whoa, whoa. The brightest mathematicians in the world held a conference to put Mathematics on a firm footing. THEY FAILED. I know that ppl like Bertrand Russell was there along with Kurt Gödel* IIRC, etc., so until the machine intelligence informs us what the world is really, we are just less hairy talking apes, and I'm not joking. So what reality are you talking about, bud? _______________________________________________ * ...and not because of his "Incompleteness Proof," btw. Mathematics itself is flawed... Don't tell me that my adv degree in Applied Mathematics and Statistics doesn't make me an Au'thor'i'ty on the subject (read like it's from South Park). Remember very few ppl know the logical fallacy of "Appeal to Authority," so I can get away with saying that.
well yueah, that's why nothing in nature can accurately be pointed to as being "Quantum" because quantum is ahuman agreed upon abstraction of natures true mechanics ;)
Ok. This is one of those videos I will need to watch a few more times if there is any hope for me to almost understand. Thanks for the rabbit hole, Arvin.🙂
Great video and breakdown. Quantum Field Theory makes more sense to me. It's how I envision things. I don't like string theory because it describes a string in a singular point of space. I just don't think that's right. That being said, I'm not a physicist or mathematician and I like everyone have a lot of questions. There's no doubt we are missing a lot of the pieces of the puzzle. I think someone will have to come along and really throw a curveball idea to help us make some progress like Einstein did. There's a lot of problems: 1. Dark Energy - Expansion of the Universe caused by who knows what 2. Dark Matter - Massless gravitational phenomena holding galaxies together but we can't figure out what it is. Right, makes sense... 3. Quantum Gravity - How gravity works on the quantum level. My feeling with this is that if we proved that gravitational waves exist, doesn't that inherently prove there is a gravitational field? Sorry I'm a novice 4. Time and Space- I for one really struggle with time and space. What even is time? We describe it as a dimension, but to me it's less a dimension and more a law of change/entropy. The more space things occupy or warp, the slower time/entropy occurs. Weird dude. 5. A million other things we don't know.... Anyway, I have to get back to my life, its a funny world. Someone smarter than me will figure it out.
Indeed. At many places "QFT" should be replaced with "Standard Model". It also depicts a bit old fashioned idea of string theory being a TOE, while most papers nowadays on string theory are about holography in which string theory is used as an embedding and calculational tool. Nice animations, though 😋
No it isn't. Because unlike 4d QFT, the "2d QFT" isn't the same as the actual theory, it's a description of a particular thing inside the theory, in a particular limit.
@@annaclarafenyo8185 ST is NOT the Standard Model, but it IS a QFT. Standard Model =/= Quantum Field Theory. QFT is just a theory of fields living in some arbitrary space-time, and String Theory is precisely that, a theory of 26 (for bosonic) or 11 (for superstring) scalar fields (the string coordinate functions) living on the 2D world-sheet traced out by the string. Yes, this looks kinda artificial since the world-sheet should be a submanifold of the background space-time, but that's only in the Nambu-Goto picture. In the Polyakov-Susskind picture, the world-sheet is it's own entity, and the background geometry actually emerges from condensates of gravitons. So yes, String Theory is indeed a Quantum Field Theory, just not a 4D Standard Model theory.
@@MessedUpSystem No. It's not that. You can't describe the full string theory with those 10 scalars (NOT 11, it's never 11) any more than you can describe the standard model fully using 4 scalars on worldlines. This is a mistaken point of view, please don't fall into it. The 'fields' of superstrings are best thought of in string field theory, or in holographic reconstruction, never as the coordinate fields. The coordinate fields are the analog of Feynman/Schwinger coordinates, they describe the path of the string, not the physical content of the theory..
@@annaclarafenyo8185 The excitations in the 2 dimensional conformal field theory which string theory is (a QFT) play the same role as the excitations in the 4 dimensional QFT we call the standard model. In the standard model you have quantum fields which have their own excitations, giving different particles falling in some representation of the Lorentz algebra. In string theory the fields are the internal degrees of freedom, i.e. the bosonic and the fermionic ones, and these excitations fall in different representations of the Lorentz algebra, which can be translated to particles in space time (one of the curious aspects of string theory: worldsheet excitations become spacetime particles, which is non-trivial!) Every representation has its own beta-function, which in a conformal field theory should vanish: this restriction gives you the equations of motion of the particles in space time. You can go one step further on the quantization level and consider string field theory in which you can create and annihilate whole string apparently, but that's something I never studied.
It is amazing how scientists like Arvin Ash can intellectually pop into the strange world of QFT/ ST and still be able to pop out back into reality translating their findings so that "normal" people "nearly" can understand!
In the layered mattresses model, would each field layer actually occupy the same space? It's puzzling to even consider what space is in relation to those many fields. From what I gather the different layers would be thought of most accurately as kind of "fused" in the same space as like different radio stations
I'm sad that Newton died 10 years before I was born, but I'm also sad that Einstein wasn't as far ahead of his time as I thought. But, maybe Nord allows for time travel too. lol
This proves that Einstein invented a time machine, went back to Newton's time, then brought Newton back with him to the 20th century. Unfortunately, Newton kept blathering away the whole trip back, so Einstein forgot to stop and kill baby Hitler.
It's a bit theoretical and not always my speed but I want to say Arvin gives a kind accessable summation of the status quo. I think your a unique voice in the field and I like your rigorous introductions to these topics. I keep hearing how strings are dead in predictions so there's no experimental data. So maybe there's something here for me
I like the evolution hypothesis that you concluded this video with, and I say that such an evolution is not only about technological evolution but also perceptual/physiological. Thank you for this wonderful explanation, Arvin, although I wish you had elaborated on the M theory a bit.
Like always, brief, concise and to the point description of comparison between QFT and ST.. Request you to make similar video describing the comparison between QFT and LQG (Loop Quantum Gravity).
How about “Tube Hypothesis” - tube hypothesis proposes that the fundamental strings in string theory are tubes (possibly two-dimensional) that facilitate vibration, by channeling the flow of spacetime.
QFT and the Standard Model are really great but it does seem like we still have a fundamental misunderstanding of the nature of reality. It could be that we'll never truly understand it, we'll just make better and better models which leads to more and more discoveries and eventual engineering concepts. That's probably the most exciting thing about physics; it's a never-ending pursuit towards understanding. There is always going to be something new.
General relativity and quantum mechanics will never be combined until we realize that they take place at different moments in time. Because causality has a speed limit (c) every point in space where you observe it from will be the closest to the present moment. When we look out into the universe, we see the past which is made of particles (GR). When we try to look at smaller and smaller sizes and distances, we are actually looking closer and closer to the present moment (QM). The wave property of particles appears when we start looking into the future of that particle. It is a probability wave because the future is probabilistic. Wave function collapse happens when we bring a particle into the present/past. GR is making measurements in the predictable past. QM is trying to make measurements of the probabilistic future.
The wave function of a photon exists first it's only when some of the energy of the wave is measured or absorbed by matter that we see it as a particle.
@@MikeSmith-cl4ixI concur. The time slice experiment performed recently somewhat backs this concept up. To me, it suggests that changes in the electromagnetic wave front caused by measurement can travel backward through the wave as the wave moves forward at causality, causing what seems like instantaneous change from a wave to a particle.
Addendum: not space! 🤦🏼♂️ My bad! Negative energy as the wave form gets twisted by the geometry of a manifold that is spinning and then runs into itself. Like a long string entering a spinning Klein Bottle, only the string is an energy wave. This way the spin can define the type of particle that comes out, if you spin 2 euclidean spaces, and from the spin, if displayed in a Minkowski space, let’s say you get 13 positions from that 2-space that describe the possible interaction of wave form into particle. Idk. I’m just playing with ideas.
Mathematically algebra is the driving force for working of QFT i.e its evolution into geometrical realities/topology and it is in the geometry of spacetime that gravitation arise. Can these be reconciled for example by an in depth description of how algebra (i.e.arrangememt of numbers as matrices and their interactions) give rise to a force which drives differential geometry? Or how these two branches of maths are connected at a more fundamental level? Would much like a video from you on this or allied topics.
A theoretical framework based on "crazy" idea that supersedes string theory has been explored since 2000 by some physicists. Their theory, published in peer reviewed journals, is based on the concept 'Clifford space', a space of oriented areas/volumes associated with fundamental physical objects. The latter objects are assumed to be representable as branes living 4D spacetime. Instead of describing them in terms of infinite number of degrees of freedom, we describe them in terms of 16 degrees of freedom. For instance, a closed string (1-brane) can be fully described in terms of four embedding functions. Instead, it can be sampled by its center of mass and the oriented area enclosed by the string. The analogous can be done for 2-branes and 3-branes. So we arrive at the 16D Clifford space or C-space. This is just a sort of configuration space. A particular matter configuration can be represented in C-space as a point that traces a world line in C-space. Another type of matter configuration can be represented in C-space as a string that sweeps a world sheet in C-space. Such string in the 16D C-space, whose signature turns out to be (8,8), can be consistently quantized. The extra dimensions for the consistency of string theory are in C-space. The underlying space is 4D spacetime. In this theory, there is no need to add extra dimension to spacetime, and thus no need for their compactification. All the problems of the usual string theory, associated with compactification and similar, vanish. Namely, there is a significant challenge in higher-dimensional theories, including string theory, regarding how to render the extra dimensions unobservable. A commonly employed approach involves assuming that the extra dimensions are compact and small. However, we can sidestep the necessity for compactification by postulating that spacetime is a subspace of a multidimensional configuration space-specifically, the space of possible matter configurations in 4D spacetime. Instead of formulating physics in spacetime, we can formulate physics in configuration space. In particular, as mentioned above, configuration space can be C-space. A potential avenue in this direction was explored in my talk titled "Extending Physics to Clifford Space: Towards the Unification of Particles and Forces, Including Gravity." I delivered this talk as part of the lecture series "Octonions, Standard Model, and Unification," held from February 24 to December 15, 2023. The video recordings of these lectures can be accessed at https:ua-cam.com/play/PLu4STGsfbix-_0BMOtpiH-_hOnBb2Xh5C.html. Specifically, the video recording of my lecture is available at ua-cam.com/video/lsYKz_uMb0c/v-deo.html. In the talk there is a section on how string theory can be consistently formulated in a target space with neutral signature (p,q) with p=q. In that setup, the higher dimensional target space is the 16D space, with signature (8,8), of the oriented areas/volumes associated with fundamental objects.
Uniting quantum mechanics and relativity will only lead to more questions, it won't be the theory of everything we hoped for. A true theory of everything must be able to account for all of the fundamental constants of nature. If a theory can be used to derive the values of all fundamental constants of nature, then we will finally have the Theory of Everything.
One question I have never seen answered in these videos about string theory. Why does gravity have to be quantized and part of a unified theory? Is there a reason for this other than it would be tidier?
Half a century of failing to connect with experiment strongly suggests that this is not a fruitful research direction. Time to try some other ideas. I agree with Sabine Hossenfelder that it makes sense to focus on resolving known experimental anomalies and logical inconsistencies -- whether or not that ultimately ends up taking us back to something like string theory.
To say that Quantum Field Theory is battling String Theory for describing reality is like saying Warren Buffet is battling the guy who sells get-rich-quick courses on UA-cam over who has more money lol
I didn't see any damage. The only somewhat tangible "prediction" is supersymmetry and that will, most likely, be found anyway, whether string theory is the source or not.
**Quantum Geometric Dynamics (QGD): A Formal Physics Description** --- **Introduction** Quantum Geometric Dynamics (QGD) is a hypothetical unified theory that aims to reconcile quantum mechanics, the Standard Model, and general relativity by introducing the **Quantum Geometric Field (QGF)**. In QGD, spacetime geometry and quantum fields emerge from the dynamics of the QGF. This framework treats geometry as a quantized entity and proposes that particles are excitations of this fundamental field. --- ### **1. Quantum Geometric Field (QGF)** **Definition**: The QGF, denoted as \( \Psi_{\text{QGF}} \), is a fundamental field permeating all of spacetime. It possesses intrinsic geometric and quantum properties. #### **Properties of the QGF** - **Quantum Nature of Geometry**: Geometry is quantized, meaning that spacetime has a discrete structure at the smallest scales (on the order of the Planck length, \( \ell_P \approx 1.616 \times 10^{-35} \) meters). - **Dynamic Dimensionality**: The effective number of spacetime dimensions \( D_{\text{eff}} \) is a function of energy scale \( E \): \[ D_{\text{eff}}(E) = 4 + f(E) \] where \( f(E) \) describes the contribution of additional dimensions at high energies. --- ### **2. Mathematical Framework** #### **2.1. Action Integral** The action \( S \) for the QGF incorporates both geometric and quantum aspects: \[ S = \int d^4x \sqrt{-g} \left( \mathcal{L}_{\text{QGF}} + \mathcal{L}_{\text{Matter}} ight) \] where: - \( g \) is the determinant of the metric tensor \( g_{\mu u} \). - \( \mathcal{L}_{\text{QGF}} \) is the Lagrangian density for the Quantum Geometric Field. - \( \mathcal{L}_{\text{Matter}} \) is the Lagrangian density for matter fields arising from excitations in the QGF. #### **2.2. QGF Lagrangian Density** The Lagrangian density \( \mathcal{L}_{\text{QGF}} \) combines geometric and quantum terms: \[ \mathcal{L}_{\text{QGF}} = -\frac{1}{2} \left( abla_\mu \Psi_{\text{QGF}} abla^\mu \Psi_{\text{QGF}}^* ight) - V(\Psi_{\text{QGF}}, abla \Psi_{\text{QGF}}) \] where: - \( abla_\mu \) is the covariant derivative. - \( V(\Psi_{\text{QGF}}, abla \Psi_{\text{QGF}}) \) is the potential term encoding self-interactions and geometric quantization effects. #### **2.3. Quantization of Geometry** Geometry is quantized via operators acting on the QGF state vectors \( |\Psi_{\text{QGF}} angle \): - **Metric Operator**: \( \hat{g}_{\mu u} \) - **Curvature Operator**: \( \hat{R}_{\mu u ho\sigma} \) These operators satisfy commutation relations analogous to those in canonical quantum gravity approaches: \[ \left[ \hat{g}_{\mu u}(x), \hat{\pi}^{ ho\sigma}(y) ight] = i \hbar \delta^ ho_\mu \delta^\sigma_ u \delta^{(4)}(x - y) \] where \( \hat{\pi}^{ ho\sigma} \) is the momentum conjugate to \( \hat{g}_{ ho\sigma} \). --- ### **3. Emergence of Particles and Forces** #### **3.1. Particles as QGF Excitations** Particles are modeled as localized excitations in the QGF: - **Field Excitations**: \( \Phi_i(x) \) represent particle fields arising from perturbations in \( \Psi_{\text{QGF}} \). - **Equation of Motion**: Derived from the variation of the action with respect to \( \Phi_i \): \[ \frac{\delta S}{\delta \Phi_i} = 0 \implies \text{Field Equations for Particles} \] #### **3.2. Forces from QGF Interactions** Fundamental forces result from interactions mediated by the QGF: - **Gauge Fields**: Gauge symmetries emerge from the invariance of \( \mathcal{L}_{\text{QGF}} \) under certain transformations of \( \Psi_{\text{QGF}} \). - **Interaction Terms**: Coupling between particle fields and geometric properties: \[ \mathcal{L}_{\text{Interaction}} = \sum_i g_i \Phi_i^\dagger \hat{\mathcal{O}} \Phi_i \] where \( \hat{\mathcal{O}} \) involves geometric operators. --- ### **4. Dynamic Dimensionality** At energy scales approaching the Planck energy (\( E_P \approx 1.22 \times 10^{19} \) GeV), additional spatial dimensions become significant. #### **4.1. Energy-Dependent Metric** The effective metric \( g_{\mu u}^{\text{eff}} \) depends on energy scale: \[ g_{\mu u}^{\text{eff}}(E) = g_{\mu u} + h_{\mu u}(E) \] where \( h_{\mu u}(E) \) encodes corrections from higher-dimensional effects. #### **4.2. Modified Dispersion Relations** Particle dispersion relations are modified at high energies: \[ E^2 = p^2 c^2 + m^2 c^4 + \Delta(E, p) \] where \( \Delta(E, p) \) accounts for dynamic dimensionality effects. --- ### **5. Elimination of Singularities** Quantization of geometry prevents singularities: - **Minimum Length Scale**: The quantized nature of spacetime introduces a minimum length scale \( \ell_{\text{min}} \geq \ell_P \). - **Regularized Curvature**: Curvature operators have finite expectation values, avoiding infinities in extreme conditions. --- ### **6. Potential Predictions and Testable Consequences** #### **6.1. Modified Gravitational Waves** - **Quantum Corrections**: Gravitational wave propagation includes quantum geometric effects. - **Observables**: Deviations from predictions of general relativity in gravitational wave data. #### **6.2. High-Energy Particle Physics** - **Anomalous Cross-Sections**: At energies near \( E_P \), particle interactions show deviations due to dynamic dimensionality. - **Possible New Particles**: Excitations corresponding to higher-dimensional modes. #### **6.3. Cosmological Implications** - **Inflationary Dynamics**: Early universe behavior influenced by QGF properties. - **Dark Matter and Energy**: Effects of quantized geometry on galactic and cosmological scales. --- ### **7. Challenges and Mathematical Development** #### **7.1. Mathematical Consistency** - **Anomalies**: Ensuring the absence of mathematical inconsistencies or anomalies in the theory. - **Renormalization**: Developing renormalization techniques suitable for quantized geometry. #### **7.2. Computational Methods** - **Numerical Simulations**: Modeling QGF dynamics requires advanced computational tools. - **Analytical Solutions**: Finding exact or approximate solutions to the field equations. --- ### **Conclusion** Quantum Geometric Dynamics offers a novel approach by treating spacetime geometry as a quantized field and unifying it with matter fields. While highly speculative, it provides a framework that could, in principle, address the unification of quantum mechanics and general relativity, eliminate singularities, and offer explanations for unexplained phenomena in cosmology. --- **Note**: As this is a hypothetical theory, the mathematical formulations provided are speculative and serve as a conceptual framework rather than a fully developed theory. Further rigorous mathematical development and experimental validation would be necessary to substantiate Quantum Geometric Dynamics.
All the fields are in our 3 spatial dimensions. They are depicted as 2D and overlapping for visualization purposes only. The fields are really 3D. They are in reality all existing at the same time in 3D.
I remember reading 'The Tao of Physics' many years ago, and desperately wanting 'Bootstrap Theory' to be correct, showing that the universe, could not, not have existed, because the equations, not only dragged it into existence, but that one constant, was the result of another, building from nothing-ish, through inevitable self assembly. It was so Gosh-Darned, beautiful. Unsurprisingly, I didn't like 'String Theory' with it's ugly random combinations of dimensions and constants, and hey! We live in a good one. Then again, Halley? Kepler? allegedly tried to show why the Earth had to be at this distance from the sun, in order that humans could live here.
Very confusing for non physics newbie. Where do these strings live? Inside the quarks or by themselves? We have seen actual electron scans of electrons and atoms. Why has’nt anyone been able to take an image of a string or multiple string together. Additional question…what gives the electrons, atoms and even strings the energy to vibrate? Always curious about that
Sorry about that. It really helps if you've seen my prior videos on this subject here: Quantum Field Theory: ua-cam.com/video/jlEovwE1oHI/v-deo.html String theory: ua-cam.com/video/3jKPJa-f3cQ/v-deo.html
String Theories are Quantum Field Theories. Just in standard model we use this Hilbert space with tetravectors. We obtain points which form a distribution. It resembles our wavefunction. Putting 2D objects there is cool because it allows more degrees of freedom to distribute energy... And the characteristic of modeling a particle which is a boson with a non repulsive counterpart.
String theory is pretty. But what has led to? What breakthroughs in physics has it brought? Is it just elegant maths? Is maths reality or just approximation?
Forgive me if this is a dumb question I am a regular blue collar guy…but at the end of the video it was mentioned that QFT could work with extra dimensions but it wasn’t needed because it worked as long as gravity was ignored…so doesn’t that mean that if QFT was reworked to include extra dimensions it could potentially include gravity?
Well, including additional dimensions in QFT essentially requires strings to make gravity make sense, so that's what String Theory really is. The extra dimensions only need inclusion to make gravity fit.
Standard model is PARTICLE PHYSICS. Subatoic particles like quarks and bosons. QUANTUM physics is different, mostly studying how probability waves interact with echother.
Arvin, the image I have is more like that extra dimensions are rather the properties of a given point in space-time. Meaning 4 for space and time; 2 for electromagnetism; 1 for temperature; 2 for the strong and weak force; etc. BTW: As gravity is not a force but a gradient of bend space-time, I don't think a Graviton is necessary.
From what I've heard in Susskind's lectures, String Theory must give QFT in its limit similarly to how quantum mechanics gives us classical mechanics in a limit. They do not oppose each other, ST just serves as a basis for QFT. Or as some other people formulate it, "ST is a QFT in such and such setting". I'm not familiar with details though, ST is way above my level.
Hi Arvin. I know it's not related to this video as such but the spin function of particles made me think. What would be the implications of a spinning universe before the big bang. After expansion would it still have spin/rotation? How would we know if we are still in a spinning expanding universe?
You would see new terms in general relativity, for one thing. The idea has been explored, but if you turn those terms on, then some really strange physics starts happening in the x-ray and gamma-ray region, where the coupling between torsion and the electromagnetic field becomes strong. This hasn't been observed, so it stands to reason that nature is torsion free.
No Einstein did not say that. He considered his geometric explanation of gravity to be a "crutch." He believed there was a superior theory that would be more complete, and not cause singularities at the limits.
Saying "tiny strings" are the foundation of reality ("quarks can't be the final, smallest things, since they are made of tiny strings trillions and trillions of time SMALLER than quarks")... is like saying "God created everything in the Universe." Neither assertion says anything. The biblical assertion asserted that the Bible "says so; who are you to question God's holy book?" String Theory, on the other hand, says: "Who are you to question the expertise who came up with symbols, numbers, charts, diagrams, equations, proofs you don't even understand?" In the Divine Approach: "He created everything, so there is no meaning to question his existence, power, or ability." In String Theory: "We told you tiny strings that vibrate sort of like guitar strings ... but unlike giant guitar strings, these pure energy strings are trillion and trillion and trillion and trillion and trillion and trillions of times smaller than guitar strings and, you know, there is nothing smaller than such pure energy loopy strings. Asking what GAVE RISE to them is meaningless, since they are the foundation of quarks, atoms, molecules, bacteria, humans, trees, planets, suns, black holes, and everything... That's not science. Saying "But we have holy/divine/pure mathematical diagrams, equations, and proofs from the most brilliant members of our species.... But if you're not happy about it, you're welcome to come up with something better, with superior mathematics," etc. still is not science.
The Standard Model doesn't explain gravity because we assume that quantum field theories are "lossless". If you add power dissipation, gravity falls out of the Model.
*Magnet suspended in Gravity - Does EM also curve space-time* ? Scientists have made it over-complicated thereby inhibiting progress. Has anyone tried integrating Electro-magnetism into General Relativity ? I don't mean quantizing gravity and integrating it into QED version 2. No no no. It's about building a unified electro-magnetic field equation (extending Einstein Field equations). When magnetic (or electric) constant is zero (or infinity) the equation simplifies to Einstein Field equation describing how mass-energy curve space-time in the absence of Electro-magnetism (leading to General Relativity). If Gravitational constant (G) is set to zero, it describes how electro-magnetism curves space-time at large distances (e.g. charged plasma getting attracted into a highly charged spinning (macro or micro) Blackhole) leading to MGM (More General Relativity). It doesn't matter if strong and weak forces cannot be integrated into EMGM (Even More General Relativity) since they're space-time curvature is extremely short in both space and time. Scientific community needs to think outside the box of quantizing everything. MGM and QED can compare notes and figure which is more accurate even though QED is currently the best QFT ever so far in accuracy of predictions.
They are both valid two different things. Just because there's a connected field doesn't mean there isn't also a connection between radiative particles and how they interact.
9:45 Your analogy for the string works well, Doc...Nice! But it seems to me that you could start even farther from the string, which would serve to strengthen your analogy further. I say this because you wouldn't be able to see the string from most distances from the string, and this seems to be the starting point for String Theory (because we can't even See these extra dimensions in the regular course of our lives). And then you can just continue with your analogy as you've already done. What do you think? 🙂
Hi @ArvinAsh. Does Roy Kerr’s work on black holes contradict general relativity? If I recall correctly, he says that singularities are not necessary in black holes
Do you have a video that talks more about why we need a graviton, i.e. a particle that mediates the "force" of gravity? My understanding is that gravity is an effect of spacetime curvature, so what does that have to do with a mediating particle?
In QFT every field is quantized and everything is described via particle creation and annihilation operators. All interactions between fields go via creation or annihilation of their quanta. When we apply this principle to Einstein's gravity field of spacetime curvature, it also becomes made of its quanta, we call them gravitons.
So matter is broken down to cells, molecules, atoms, and quarks. Atoms have 99.9 empty space, and quarks seem to flash in and out of existence . So the closer we get to sub atomic level the more we do not exist. This makes perfect sense!
Spacetime is simply empty, at all levels. It does have an additive and locally preserved system property called energy. Everything can be explained with that alone.
7:00 "we know that gravity propagates at the speed of light". This is bothersome because gravitational waves have nothing to do with light. So there must be some deeper connection between the speeds of the two types of wave. I would like to see a whole video on this subject. I think viewers would be very interested in your thoughts on this problem.
The speed of light is the speed of causality. Gravitational waves only propagate at almost the speed of light because they we free. In strongly gravitating systems gravity slows down just as much as light does.
I dont understand why gravity needs to be found in a string or particle. Why cant gravity just be an effect from mass being in space/time. Cant gravity just be space getting warped by mass? Its just the bending of space/time and not an actual thing. The thing(space/time) getting bent is something, but gravity is just whats happening, the bend and warping.
That is the problem is that we only know that gravity is the warping of space time from mass, there is an explanation or way to quantify most things in the universe and so why would gravity be an exception. Unless this universe was programmed and the code for gravity is entirely separate
Theres two local black holes that were just mapped. The magnetic fields propagating in totality in the house of mirrors averages out at focal points in the space time, producing reality. M87 and SgrA* black holes are currently eating stars that are propagating the gravity/alfven waves, along with mass attraction, and other wave forms from the universe
This is underselling quantum field theory. Any local (with other modest constrains) quantum theory are equivalent to a quantum field theory at low energy. In this sense, quantum field theory would always describe reality at low energy. This idea is Wilson's renormalization. This is similar to no matter what smooth function (with other modest constrains) you have, its behavior at low energy (global minimum) would always be like a 2nd degree polynomial. The 2nd degree polynomial would always describe such functions at low energy... similar to how quantum field theory would always describe such functions at low energy. The version of quantum field theory we have (core theory or standard model + naive gravity) can in principle already explain all daily phenomenon like biological, neuro science (and anything that is not made from billions dollars particle accelerators which is the reference for low/high energy)
Thanks to our sponsor, we could make this video. Please support us by clicking the link: Get 4 months extra on a 2 year plan here: nordvpn.com/arvin. It’s risk free with Nord’s 30 day money-back guarantee!
I remember when this channel had 530 subscribers that's when I subbed this channel had grown more than any other channel I have seen it's unreal 😮
String theory - if you need 10 dimensions to make the math work, it is right off the bat delusional as Penrose said.
Quantum field theory - if you need infinities to make predictions right, it's more delusional than string theory.
Maybe the “Tube Hypothesis” could further string theory and possibly quantum field theory?
- tube hypothesis proposes that the fundamental strings in string theory are tubes (possibly two-dimensional) that facilitate vibration, by channeling the flow of spacetime.
What are the particles that make a quantum harmonic oscillator.
It was a fun way to incorporate NordVPN into your science!
but the idea that a graviton being a force carrier conflicts with the idea that gravity is not a force but a twisting of space-time.
@harper262 what you are saying is exactly the problem physicists are trying to resolve. General Relativity says gravity is warping of spacetime due to mass-energy. QFT says fundamental forces, of which gravity is one, is mediated through particles. We need a new theory to reconcile the two descriptions.
But QFT says nothing about gravity. That's the problem. Gravity isn't a force but can be described in terms of gauge fields. In QFT gauge fields correspond to force carriers and so gravity is assumed to be a force. However, there is no trivial way to quantize gravity and that's where the problem lies - providing a quantized field-theoretic description of gravity @@Johnny-bm7ry.
That’s not what the issue is.
You can write down a perfectly good theory of quantum gravity in 2 dimensions, so whatever intuitions we have about general relativity aren’t really a problem.
The problem is that quantized general relativity in 4 dimensions is nonrenormalizable. You need to include an infinite number of free parameters to get results that aren’t obviously unphysical infinities. This is a huge problem and physicists really don’t like it.
Does the earth still have gravity if one day suddenly stopped spinning around (Rotation) ??
@@Mrorlgloth yes. All it needs is mass.
Exploring theories, even when they eventually don't give us all answers, is never a waste. It enriches our knowledge and often points us in a new direction.
I'm absolutely sure we will find the other missing dimensions in the same place my dryer loses my socks.
Check your local paper, or online, for the next Single Sock Symposium (SX3) in your area. The best place to find that matching single sock you've been looking for that you lost through the dryer wormhole.
Your socks are in superposition, waiting to be measured.
@@alfadog67 then they must also be entangled because I'm missing whole pairs.
@martinblank-th2kx does that mean my socks disappeared at light speed?
Since your dryer lives in a symmetrical spacetime-system (see Noether theorem), eradication of your socks would violate conservation of energy (aka mass). There are three things, that hold in symmetrical systems - otherwise our universe would collapse: i) conservation of energy, ii) conservation of momentum, iii) Pauli's exclusion principle. Every single known physical law obeys these basic principles.
I have an idea on how to visualize string theory's extra dimensions. As it's been said that it's impossible for our brains to visualize extra dimensions, this can bypassed by the assertion that the extra dimensions are compactified, so the visualization can remain 3D. Each of the extra compactified dimensions can be visualized by giving an object extra visual properties but keeping their 3D location the same. Imagine a ball. You can visualize it moving through the first 4 dimensions by moving it around and watching it in motion. Then imagine a 5th dimension: moving through a color gradient from blue to red. So now you can move a ball through regular 4D space (its motion being the 4th dimension), and you can move it back and forth through the 5th by changing its color from red to blue or back. You can then add additional visual properties to represent further dimensions. Imagine a conversation between 2 particles: "Hey, I'm here where you told us to meet, at the exact coordinates and at the right time, but I don't see you", "Your x,y,z is correct, and I'm still here. However, you need to come bluer to me. You're too far away off in the red. Come bluer and you'll see me" "Oh ok, I see you now. I must've taken the wrong turn at purple". If you take away an object's innate visual description and give it to the coordinate system, you can represent another dimension by having it represent another dimension's gradient by making it be an arrow that can point in various directions, each direction representing a point on that dimension's gradient. Like an arrow on a speedometer pointing to numbers, it could be pointing at its representive coordinate for that dimension. So if the 6th dimension were represented by a fuel fage, those particles can extend their conversation: "let's go for a stroll. We can keep our x,y,z coordinates, stay in the blue, but we can take a stroll from full to empty and then back. 1 lap". Since motion in the extra dimensions doesn't affect the x,y,z coordinates, this should work, as it remains conistent with the 3D world, borrowing some of its attributes to represent motion in dimensions we can't see, the same way that worldlines on a spacetime diagram borrow the Y dimension to represent time.
U r the first one to have a similar idea as mine..
Honestly I don't like this..
I thought that was an original idea of mine which only I thought of.. Feeling odd to see someone with similar thought process..
My idea was just the same..
It's like we all are living in red 3D space with yellow and other colours 3D space overlaying ours.. .
Imagine we living inside a Rubik's cube with each face colour emitting that color light and we living in red 3D face..
All 6 sides emitting thier colour ..
They are the other dimensions we can't access coz we are not just colour blind in our eyes but colour blind in our bodies as a whole..
And some higher being who is not colour blind can see us all 6 coloured beings with his eyes...
Just like we can see video games character but they can't see us or know of us..
@@godspeed5428 I have also considered the possibility that qualities associated with sensory experience could be considered as dimensions and formalized mathematically. Though I hadn't considered it in nearly so much depth as OP. It would certainly jive with the idea that consciousness plays some role in physics.
Wow! I appreciate your knowledge 😮
@@godspeed5428 makes sense
@@ero- thanks
When talking about quantifying gravity, all we hear about is String theory. I wish there were more videos about loop quantum gravity, it's fascinating
As doctor who knows absolutely nothing about physics, but loves to learn about it, this video was amazing!!! Keep it up!
A little late to the party but at 11:14
i like the birth date and date of death for each forefather of mathematics and science being exactly true to fact.
That's why I like arvinash
The Nord VPN Placement was hilarious :D
Is this some kind of stock app joke Im too ReVanced to understand?
Great job on the commercial insertion!
@@drasiella it was one of arvin's smoothest segues
"warp!"
😂
Nerd VPN
The visualizations are very helpful
6:51 this is my first time seeing a string theory equation
Don't worry, you haven't been missing much. String Theory has nothing to do with reality and everything to do with the University system collecting billions of dollars in tuition $$$ from physics students. I can't imagine how cognitively compromised I would have to be before I would agree to pay an institution that much $$$ for a degree in science fiction.
and it is not one, just a misleading complicated formula one of many one can write.
@@ika5666looks fine to me, it’s an amplitude of genus g written as a sum over moduli. standard.
@@kashu7691 I see it, but it is not the "string theory equation".
@@ika5666 i would say it is, perturbative string theory is entirely equivalent to the set of all its amplitudes
Me watching not understanding any of this but really interested
SAMEE. I'm only a physics undergrad so I watched twice in a row trying to understand
Same here 😅 I watched it and understood approximately 14% of it.
Saving this video and coming back to it when I get a little older
Fizyka pozwala wznieść się wyższy poziom niezrozumienia 😁
That reminds me of a Brian Regan joke about string theory.
I see an arvin upload , i click real quick
I remember taking calculus in college. We were assigned the problem of rotating the y=1/x function around the x-axis to form a cone. Then calculate both the volume and surface area of the cone from x=1 to infinity. The result was a cone with a finite volume, but an infinite surface area. In other words, you could fill it with paint, but couldn't paint the inside.
My point : Just because the math says something .... doesn't mean it reflects reality.
Math can reflect reality, as you say, to a very high degree. One might even say it's unreasonable effective at it. 😏
Just never try to work infinity into those equations. 😂
Until you define what you mean by 'Reality', you can't say whether math is an accurate description of it or not. If your definition of reality includes the role of the (human) observer, then you have to use math to describe consciousness....good luck with that ...
...and I thought before I stopped using my DDCs, like Blender to make computer graphics, that was hard... ua-cam.com/video/w0bnigQ17JE/v-deo.html What's the point now that Sora and stuff like that does the same thing with a few prompts.
@@portugalforme1198 Whoa, whoa, whoa. The brightest mathematicians in the world held a conference to put Mathematics on a firm footing.
THEY FAILED. I know that ppl like Bertrand Russell was there along with Kurt Gödel* IIRC, etc., so until the machine intelligence informs us what the world is really, we are just less hairy talking apes, and I'm not joking.
So what reality are you talking about, bud?
_______________________________________________
* ...and not because of his "Incompleteness Proof," btw. Mathematics itself is flawed... Don't tell me that my adv degree in Applied Mathematics and Statistics doesn't make me an Au'thor'i'ty on the subject (read like it's from South Park).
Remember very few ppl know the logical fallacy of "Appeal to Authority," so I can get away with saying that.
well yueah, that's why nothing in nature can accurately be pointed to as being "Quantum" because quantum is ahuman agreed upon abstraction of natures true mechanics ;)
Ok. This is one of those videos I will need to watch a few more times if there is any hope for me to almost understand. Thanks for the rabbit hole, Arvin.🙂
Great video and breakdown. Quantum Field Theory makes more sense to me. It's how I envision things. I don't like string theory because it describes a string in a singular point of space. I just don't think that's right. That being said, I'm not a physicist or mathematician and I like everyone have a lot of questions. There's no doubt we are missing a lot of the pieces of the puzzle. I think someone will have to come along and really throw a curveball idea to help us make some progress like Einstein did. There's a lot of problems:
1. Dark Energy - Expansion of the Universe caused by who knows what
2. Dark Matter - Massless gravitational phenomena holding galaxies together but we can't figure out what it is. Right, makes sense...
3. Quantum Gravity - How gravity works on the quantum level. My feeling with this is that if we proved that gravitational waves exist, doesn't that inherently prove there is a gravitational field? Sorry I'm a novice
4. Time and Space- I for one really struggle with time and space. What even is time? We describe it as a dimension, but to me it's less a dimension and more a law of change/entropy. The more space things occupy or warp, the slower time/entropy occurs. Weird dude.
5. A million other things we don't know....
Anyway, I have to get back to my life, its a funny world. Someone smarter than me will figure it out.
At 11:15 the dates of birth of Newton and Einstein are switched
Beautiful explanation, well done! You're one of the best with your unique style!
Always a treat to watch Arvin 😊
Actually, String Theory is a type of Quantum Field Theory, it is a QFT of D scalar fields living on the 2D world-sheet of the string
Indeed. At many places "QFT" should be replaced with "Standard Model".
It also depicts a bit old fashioned idea of string theory being a TOE, while most papers nowadays on string theory are about holography in which string theory is used as an embedding and calculational tool. Nice animations, though 😋
No it isn't. Because unlike 4d QFT, the "2d QFT" isn't the same as the actual theory, it's a description of a particular thing inside the theory, in a particular limit.
@@annaclarafenyo8185 ST is NOT the Standard Model, but it IS a QFT. Standard Model =/= Quantum Field Theory. QFT is just a theory of fields living in some arbitrary space-time, and String Theory is precisely that, a theory of 26 (for bosonic) or 11 (for superstring) scalar fields (the string coordinate functions) living on the 2D world-sheet traced out by the string. Yes, this looks kinda artificial since the world-sheet should be a submanifold of the background space-time, but that's only in the Nambu-Goto picture. In the Polyakov-Susskind picture, the world-sheet is it's own entity, and the background geometry actually emerges from condensates of gravitons. So yes, String Theory is indeed a Quantum Field Theory, just not a 4D Standard Model theory.
@@MessedUpSystem No. It's not that. You can't describe the full string theory with those 10 scalars (NOT 11, it's never 11) any more than you can describe the standard model fully using 4 scalars on worldlines. This is a mistaken point of view, please don't fall into it.
The 'fields' of superstrings are best thought of in string field theory, or in holographic reconstruction, never as the coordinate fields. The coordinate fields are the analog of Feynman/Schwinger coordinates, they describe the path of the string, not the physical content of the theory..
@@annaclarafenyo8185 The excitations in the 2 dimensional conformal field theory which string theory is (a QFT) play the same role as the excitations in the 4 dimensional QFT we call the standard model. In the standard model you have quantum fields which have their own excitations, giving different particles falling in some representation of the Lorentz algebra. In string theory the fields are the internal degrees of freedom, i.e. the bosonic and the fermionic ones, and these excitations fall in different representations of the Lorentz algebra, which can be translated to particles in space time (one of the curious aspects of string theory: worldsheet excitations become spacetime particles, which is non-trivial!) Every representation has its own beta-function, which in a conformal field theory should vanish: this restriction gives you the equations of motion of the particles in space time.
You can go one step further on the quantization level and consider string field theory in which you can create and annihilate whole string apparently, but that's something I never studied.
It is amazing how scientists like Arvin Ash can intellectually pop into the strange world of QFT/ ST and still be able to pop out back into reality translating their findings so that "normal" people "nearly" can understand!
He's just doing propaganda against string theory.
In the layered mattresses model, would each field layer actually occupy the same space? It's puzzling to even consider what space is in relation to those many fields. From what I gather the different layers would be thought of most accurately as kind of "fused" in the same space as like different radio stations
There's no way I'd have professors as interesting as you. Without fully studying these topics, I'm glad info is available like this on youtube.
I'm sad that Newton died 10 years before I was born, but I'm also sad that Einstein wasn't as far ahead of his time as I thought. But, maybe Nord allows for time travel too. lol
Are you saying you're 296 years old? :))
This proves that Einstein invented a time machine, went back to Newton's time, then brought Newton back with him to the 20th century. Unfortunately, Newton kept blathering away the whole trip back, so Einstein forgot to stop and kill baby Hitler.
He is demon a son of witch
It's a bit theoretical and not always my speed but I want to say Arvin gives a kind accessable summation of the status quo. I think your a unique voice in the field and I like your rigorous introductions to these topics. I keep hearing how strings are dead in predictions so there's no experimental data. So maybe there's something here for me
I like the evolution hypothesis that you concluded this video with, and I say that such an evolution is not only about technological evolution but also perceptual/physiological. Thank you for this wonderful explanation, Arvin, although I wish you had elaborated on the M theory a bit.
Like always, brief, concise and to the point description of comparison between QFT and ST.. Request you to make similar video describing the comparison between QFT and LQG (Loop Quantum Gravity).
The thing I always wonder is what gets the mattress vibrating in the first place?
In my case, it takes an alarm clock that can't be ignored.
Thanks!
Thanks so much!
How about “Tube Hypothesis”
- tube hypothesis proposes that the fundamental strings in string theory are tubes (possibly two-dimensional) that facilitate vibration, by channeling the flow of spacetime.
🤨
QFT and the Standard Model are really great but it does seem like we still have a fundamental misunderstanding of the nature of reality. It could be that we'll never truly understand it, we'll just make better and better models which leads to more and more discoveries and eventual engineering concepts. That's probably the most exciting thing about physics; it's a never-ending pursuit towards understanding. There is always going to be something new.
You are right you are always right
So cool! Thanks for the detailed explanation 😊
Very, very interesting video! Thank you Arvin Ash! 👍👍👏
General relativity and quantum mechanics will never be combined until we realize that they take place at different moments in time. Because causality has a speed limit (c) every point in space where you observe it from will be the closest to the present moment. When we look out into the universe, we see the past which is made of particles (GR). When we try to look at smaller and smaller sizes and distances, we are actually looking closer and closer to the present moment (QM). The wave property of particles appears when we start looking into the future of that particle. It is a probability wave because the future is probabilistic. Wave function collapse happens when we bring a particle into the present/past. GR is making measurements in the predictable past. QM is trying to make measurements of the probabilistic future.
well we can say that
Interesting observation.
Also, Gravity is not a force, whereas Quantum is force.
I've never thought about it that way, that's a pretty clever concept. I don't know if it's accurate, but I like it.
The wave function of a photon exists first it's only when some of the energy of the wave is measured or absorbed by matter that we see it as a particle.
@@MikeSmith-cl4ixI concur. The time slice experiment performed recently somewhat backs this concept up. To me, it suggests that changes in the electromagnetic wave front caused by measurement can travel backward through the wave as the wave moves forward at causality, causing what seems like instantaneous change from a wave to a particle.
String Hypothesis*
Nice explanation, easy to understand.
I actually stopped watching another video just to click on this when I saw the notification.
Same 😂
8:26 - Holograms can appear to move as Time allows everything to move - giving the perception of three dimensions.
Not strings, but energetic waves that get twisted together by time to form particles, whose negative space within the knot is gravity.
Whats negative space
Addendum: not space! 🤦🏼♂️ My bad! Negative energy as the wave form gets twisted by the geometry of a manifold that is spinning and then runs into itself. Like a long string entering a spinning Klein Bottle, only the string is an energy wave. This way the spin can define the type of particle that comes out, if you spin 2 euclidean spaces, and from the spin, if displayed in a Minkowski space, let’s say you get 13 positions from that 2-space that describe the possible interaction of wave form into particle. Idk. I’m just playing with ideas.
Mathematically algebra is the driving force for working of QFT i.e its evolution into geometrical realities/topology and it is in the geometry of spacetime that gravitation arise. Can these be reconciled for example by an in depth description of how algebra (i.e.arrangememt of numbers as matrices and their interactions) give rise to a force which drives differential geometry? Or how these two branches of maths are connected at a more fundamental level? Would much like a video from you on this or allied topics.
A theoretical framework based on "crazy" idea that supersedes string theory has been explored since 2000 by some physicists. Their theory, published in peer reviewed journals, is based on the concept 'Clifford space', a space of oriented areas/volumes associated with fundamental physical objects. The latter objects are assumed to be representable as branes living 4D spacetime. Instead of describing them in terms of infinite number of degrees of freedom, we describe them in terms of 16 degrees of freedom. For instance, a closed string (1-brane) can be fully described in terms of four embedding functions. Instead, it can be sampled by its center of mass and the oriented area enclosed by the string. The analogous can be done for 2-branes and 3-branes. So we arrive at the 16D Clifford space or C-space. This is just a sort of configuration space. A particular matter configuration can be represented in C-space as a point that traces a world line in C-space. Another type of matter configuration can be represented in C-space as a string that sweeps a world sheet in C-space. Such string in the 16D C-space, whose signature turns out to be (8,8), can be consistently quantized. The extra dimensions for the consistency of string theory are in C-space. The underlying space is 4D spacetime. In this theory, there is no need to add extra dimension to spacetime, and thus no need for their compactification. All the problems of the usual string theory, associated with compactification and similar, vanish.
Namely, there is a significant challenge in higher-dimensional theories, including string theory, regarding how to render the extra dimensions unobservable. A commonly employed approach involves assuming that the extra dimensions are compact and small. However, we can sidestep the necessity for compactification by postulating that spacetime is a subspace of a multidimensional configuration space-specifically, the space of possible matter configurations in 4D spacetime. Instead of formulating physics in spacetime, we can formulate physics in configuration space. In particular, as mentioned above, configuration space can be C-space.
A potential avenue in this direction was explored in my talk titled "Extending Physics to Clifford Space: Towards the Unification of Particles and Forces, Including Gravity." I delivered this talk as part of the lecture series "Octonions, Standard Model, and Unification," held from February 24 to December 15, 2023.
The video recordings of these lectures can be accessed at https:ua-cam.com/play/PLu4STGsfbix-_0BMOtpiH-_hOnBb2Xh5C.html. Specifically, the video recording of my lecture is available at ua-cam.com/video/lsYKz_uMb0c/v-deo.html.
In the talk there is a section on how string theory can be consistently formulated in a target space with neutral signature (p,q) with p=q. In that setup, the higher dimensional target space is the 16D space, with signature (8,8), of the oriented areas/volumes associated with fundamental objects.
Actually watched the ad because the lead into it earned it
Excellent, Arvin.
Uniting quantum mechanics and relativity will only lead to more questions, it won't be the theory of everything we hoped for. A true theory of everything must be able to account for all of the fundamental constants of nature. If a theory can be used to derive the values of all fundamental constants of nature, then we will finally have the Theory of Everything.
The Nord VPN grift/ad was genius placement lolol
How come photon with zero mass exists? If it exists, it's gotta be made of something, right? 🤔
One question I have never seen answered in these videos about string theory. Why does gravity have to be quantized and part of a unified theory? Is there a reason for this other than it would be tidier?
I was literally blown away by the way of your explanation😮👏
Half a century of failing to connect with experiment strongly suggests that this is not a fruitful research direction. Time to try some other ideas. I agree with Sabine Hossenfelder that it makes sense to focus on resolving known experimental anomalies and logical inconsistencies -- whether or not that ultimately ends up taking us back to something like string theory.
An Oscar nomination for Arvin and his NordVPN act please :D
GOOD, thank you for this explanations. I like the comparison 👍 And only crazy ideas leads to new knowledge, by falsifying or proving.
To say that Quantum Field Theory is battling String Theory for describing reality is like saying Warren Buffet is battling the guy who sells get-rich-quick courses on UA-cam over who has more money lol
Could you do a video analysing the relationship between Quantum Field Theory (QFT) and Loop Quantum Gravity?
What's truly unmeasurable is the amount of damage string theory did to modern physics over the decades.
I didn't see any damage. The only somewhat tangible "prediction" is supersymmetry and that will, most likely, be found anyway, whether string theory is the source or not.
Thanks for this video
**Quantum Geometric Dynamics (QGD): A Formal Physics Description**
---
**Introduction**
Quantum Geometric Dynamics (QGD) is a hypothetical unified theory that aims to reconcile quantum mechanics, the Standard Model, and general relativity by introducing the **Quantum Geometric Field (QGF)**. In QGD, spacetime geometry and quantum fields emerge from the dynamics of the QGF. This framework treats geometry as a quantized entity and proposes that particles are excitations of this fundamental field.
---
### **1. Quantum Geometric Field (QGF)**
**Definition**: The QGF, denoted as \( \Psi_{\text{QGF}} \), is a fundamental field permeating all of spacetime. It possesses intrinsic geometric and quantum properties.
#### **Properties of the QGF**
- **Quantum Nature of Geometry**: Geometry is quantized, meaning that spacetime has a discrete structure at the smallest scales (on the order of the Planck length, \( \ell_P \approx 1.616 \times 10^{-35} \) meters).
- **Dynamic Dimensionality**: The effective number of spacetime dimensions \( D_{\text{eff}} \) is a function of energy scale \( E \):
\[
D_{\text{eff}}(E) = 4 + f(E)
\]
where \( f(E) \) describes the contribution of additional dimensions at high energies.
---
### **2. Mathematical Framework**
#### **2.1. Action Integral**
The action \( S \) for the QGF incorporates both geometric and quantum aspects:
\[
S = \int d^4x \sqrt{-g} \left( \mathcal{L}_{\text{QGF}} + \mathcal{L}_{\text{Matter}}
ight)
\]
where:
- \( g \) is the determinant of the metric tensor \( g_{\mu
u} \).
- \( \mathcal{L}_{\text{QGF}} \) is the Lagrangian density for the Quantum Geometric Field.
- \( \mathcal{L}_{\text{Matter}} \) is the Lagrangian density for matter fields arising from excitations in the QGF.
#### **2.2. QGF Lagrangian Density**
The Lagrangian density \( \mathcal{L}_{\text{QGF}} \) combines geometric and quantum terms:
\[
\mathcal{L}_{\text{QGF}} = -\frac{1}{2} \left(
abla_\mu \Psi_{\text{QGF}}
abla^\mu \Psi_{\text{QGF}}^*
ight) - V(\Psi_{\text{QGF}},
abla \Psi_{\text{QGF}})
\]
where:
- \(
abla_\mu \) is the covariant derivative.
- \( V(\Psi_{\text{QGF}},
abla \Psi_{\text{QGF}}) \) is the potential term encoding self-interactions and geometric quantization effects.
#### **2.3. Quantization of Geometry**
Geometry is quantized via operators acting on the QGF state vectors \( |\Psi_{\text{QGF}}
angle \):
- **Metric Operator**: \( \hat{g}_{\mu
u} \)
- **Curvature Operator**: \( \hat{R}_{\mu
u
ho\sigma} \)
These operators satisfy commutation relations analogous to those in canonical quantum gravity approaches:
\[
\left[ \hat{g}_{\mu
u}(x), \hat{\pi}^{
ho\sigma}(y)
ight] = i \hbar \delta^
ho_\mu \delta^\sigma_
u \delta^{(4)}(x - y)
\]
where \( \hat{\pi}^{
ho\sigma} \) is the momentum conjugate to \( \hat{g}_{
ho\sigma} \).
---
### **3. Emergence of Particles and Forces**
#### **3.1. Particles as QGF Excitations**
Particles are modeled as localized excitations in the QGF:
- **Field Excitations**: \( \Phi_i(x) \) represent particle fields arising from perturbations in \( \Psi_{\text{QGF}} \).
- **Equation of Motion**: Derived from the variation of the action with respect to \( \Phi_i \):
\[
\frac{\delta S}{\delta \Phi_i} = 0 \implies \text{Field Equations for Particles}
\]
#### **3.2. Forces from QGF Interactions**
Fundamental forces result from interactions mediated by the QGF:
- **Gauge Fields**: Gauge symmetries emerge from the invariance of \( \mathcal{L}_{\text{QGF}} \) under certain transformations of \( \Psi_{\text{QGF}} \).
- **Interaction Terms**: Coupling between particle fields and geometric properties:
\[
\mathcal{L}_{\text{Interaction}} = \sum_i g_i \Phi_i^\dagger \hat{\mathcal{O}} \Phi_i
\]
where \( \hat{\mathcal{O}} \) involves geometric operators.
---
### **4. Dynamic Dimensionality**
At energy scales approaching the Planck energy (\( E_P \approx 1.22 \times 10^{19} \) GeV), additional spatial dimensions become significant.
#### **4.1. Energy-Dependent Metric**
The effective metric \( g_{\mu
u}^{\text{eff}} \) depends on energy scale:
\[
g_{\mu
u}^{\text{eff}}(E) = g_{\mu
u} + h_{\mu
u}(E)
\]
where \( h_{\mu
u}(E) \) encodes corrections from higher-dimensional effects.
#### **4.2. Modified Dispersion Relations**
Particle dispersion relations are modified at high energies:
\[
E^2 = p^2 c^2 + m^2 c^4 + \Delta(E, p)
\]
where \( \Delta(E, p) \) accounts for dynamic dimensionality effects.
---
### **5. Elimination of Singularities**
Quantization of geometry prevents singularities:
- **Minimum Length Scale**: The quantized nature of spacetime introduces a minimum length scale \( \ell_{\text{min}} \geq \ell_P \).
- **Regularized Curvature**: Curvature operators have finite expectation values, avoiding infinities in extreme conditions.
---
### **6. Potential Predictions and Testable Consequences**
#### **6.1. Modified Gravitational Waves**
- **Quantum Corrections**: Gravitational wave propagation includes quantum geometric effects.
- **Observables**: Deviations from predictions of general relativity in gravitational wave data.
#### **6.2. High-Energy Particle Physics**
- **Anomalous Cross-Sections**: At energies near \( E_P \), particle interactions show deviations due to dynamic dimensionality.
- **Possible New Particles**: Excitations corresponding to higher-dimensional modes.
#### **6.3. Cosmological Implications**
- **Inflationary Dynamics**: Early universe behavior influenced by QGF properties.
- **Dark Matter and Energy**: Effects of quantized geometry on galactic and cosmological scales.
---
### **7. Challenges and Mathematical Development**
#### **7.1. Mathematical Consistency**
- **Anomalies**: Ensuring the absence of mathematical inconsistencies or anomalies in the theory.
- **Renormalization**: Developing renormalization techniques suitable for quantized geometry.
#### **7.2. Computational Methods**
- **Numerical Simulations**: Modeling QGF dynamics requires advanced computational tools.
- **Analytical Solutions**: Finding exact or approximate solutions to the field equations.
---
### **Conclusion**
Quantum Geometric Dynamics offers a novel approach by treating spacetime geometry as a quantized field and unifying it with matter fields. While highly speculative, it provides a framework that could, in principle, address the unification of quantum mechanics and general relativity, eliminate singularities, and offer explanations for unexplained phenomena in cosmology.
---
**Note**: As this is a hypothetical theory, the mathematical formulations provided are speculative and serve as a conceptual framework rather than a fully developed theory. Further rigorous mathematical development and experimental validation would be necessary to substantiate Quantum Geometric Dynamics.
love this
What is the difference between overlapping fields and multiple dimensions?
All the fields are in our 3 spatial dimensions. They are depicted as 2D and overlapping for visualization purposes only. The fields are really 3D. They are in reality all existing at the same time in 3D.
Virtual particle spin laws and rules?
Quantum entanglement and virtual particles?
Gravity and virtual particle interactions and actions?
Excellent video my friend!
From a philosophical point of view, it seems that there is a supergravity that transcends the entire physical framework
So basically we are not any closer
I remember reading 'The Tao of Physics' many years ago, and desperately wanting 'Bootstrap Theory' to be correct, showing that the universe, could not, not have existed, because the equations, not only dragged it into existence, but that one constant, was the result of another, building from nothing-ish, through inevitable self assembly. It was so Gosh-Darned, beautiful. Unsurprisingly, I didn't like 'String Theory' with it's ugly random combinations of dimensions and constants, and hey! We live in a good one. Then again, Halley? Kepler? allegedly tried to show why the Earth had to be at this distance from the sun, in order that humans could live here.
Very confusing for non physics newbie. Where do these strings live? Inside the quarks or by themselves? We have seen actual electron scans of electrons and atoms. Why has’nt anyone been able to take an image of a string or multiple string together.
Additional question…what gives the electrons, atoms and even strings the energy to vibrate? Always curious about that
Sorry about that. It really helps if you've seen my prior videos on this subject here: Quantum Field Theory: ua-cam.com/video/jlEovwE1oHI/v-deo.html
String theory: ua-cam.com/video/3jKPJa-f3cQ/v-deo.html
THANKS FOR THE VIDEO BROTHER 💙🙏💙🙏💙🙏💙🙏
Like many other vids..but especially this one, learned and memorised some things very easily..was veeeery goodly explained!!
String Theories are Quantum Field Theories.
Just in standard model we use this Hilbert space with tetravectors.
We obtain points which form a distribution. It resembles our wavefunction.
Putting 2D objects there is cool because it allows more degrees of freedom to distribute energy... And the characteristic of modeling a particle which is a boson with a non repulsive counterpart.
This caused me to rewatch Matt O'Dowd's discussion (PBS Spacetime) of a graviton detector where the Schwarzschild radius emerges.
String theory is pretty. But what has led to? What breakthroughs in physics has it brought? Is it just elegant maths? Is maths reality or just approximation?
Forgive me if this is a dumb question I am a regular blue collar guy…but at the end of the video it was mentioned that QFT could work with extra dimensions but it wasn’t needed because it worked as long as gravity was ignored…so doesn’t that mean that if QFT was reworked to include extra dimensions it could potentially include gravity?
Well, including additional dimensions in QFT essentially requires strings to make gravity make sense, so that's what String Theory really is. The extra dimensions only need inclusion to make gravity fit.
Your videos are awesome & to the point to the main Subject...
Standard model is PARTICLE PHYSICS. Subatoic particles like quarks and bosons. QUANTUM physics is different, mostly studying how probability waves interact with echother.
Arvin, the image I have is more like that extra dimensions are rather the properties of a given point in space-time. Meaning 4 for space and time; 2 for electromagnetism; 1 for temperature; 2 for the strong and weak force; etc. BTW: As gravity is not a force but a gradient of bend space-time, I don't think a Graviton is necessary.
Temperature wouldn't have it's own dimension since it's just vibration, a system made of just a single particle has no temperature
From what I've heard in Susskind's lectures, String Theory must give QFT in its limit similarly to how quantum mechanics gives us classical mechanics in a limit. They do not oppose each other, ST just serves as a basis for QFT. Or as some other people formulate it, "ST is a QFT in such and such setting". I'm not familiar with details though, ST is way above my level.
Thanks for the info
Hi Arvin. I know it's not related to this video as such but the spin function of particles made me think.
What would be the implications of a spinning universe before the big bang. After expansion would it still have spin/rotation? How would we know if we are still in a spinning expanding universe?
You would see new terms in general relativity, for one thing. The idea has been explored, but if you turn those terms on, then some really strange physics starts happening in the x-ray and gamma-ray region, where the coupling between torsion and the electromagnetic field becomes strong. This hasn't been observed, so it stands to reason that nature is torsion free.
@ArvinAsh what do you think of Nassim Harramein's work? Is he's blowing hot air, or do you think he's on to something?
Thank you for new video, always a pleasure!
At 11:14 the dates indicated are changed
Actually, in the String Theory of the universe, these dates are correct. The strings pull you back and forth through time, like a yo-yo.
Didn't Einstein say gravity isn't a force but an acceleration due to warped spacetime. So it can't be quantized.
No Einstein did not say that. He considered his geometric explanation of gravity to be a "crutch." He believed there was a superior theory that would be more complete, and not cause singularities at the limits.
Saying "tiny strings" are the foundation of reality ("quarks can't be the final, smallest things, since they are made of tiny strings trillions and trillions of time SMALLER than quarks")... is like saying "God created everything in the Universe."
Neither assertion says anything.
The biblical assertion asserted that the Bible "says so; who are you to question God's holy book?"
String Theory, on the other hand, says: "Who are you to question the expertise who came up with symbols, numbers, charts, diagrams, equations, proofs you don't even understand?"
In the Divine Approach: "He created everything, so there is no meaning to question his existence, power, or ability."
In String Theory:
"We told you tiny strings that vibrate sort of like guitar strings ... but unlike giant guitar strings, these pure energy strings are trillion and trillion and trillion and trillion and trillion and trillions of times smaller than guitar strings and, you know, there is nothing smaller than such pure energy loopy strings. Asking what GAVE RISE to them is meaningless, since they are the foundation of quarks, atoms, molecules, bacteria, humans, trees, planets, suns, black holes, and everything...
That's not science.
Saying "But we have holy/divine/pure mathematical diagrams, equations, and proofs from the most brilliant members of our species.... But if you're not happy about it, you're welcome to come up with something better, with superior mathematics," etc. still is not science.
Takes a brave man to take on Feynman. Good effort but how many dimensions can be invented to square the numbers ?
Great sharing, my friends.
I am thrilled to see you back the The Sciences Pages. Here's to you ARVIN.!!!
Newton thought light traveled as corpuscles. Einstien agreed with him.
The Standard Model doesn't explain gravity because we assume that quantum field theories are "lossless". If you add power dissipation, gravity falls out of the Model.
Research papers please.
*Magnet suspended in Gravity - Does EM also curve space-time* ?
Scientists have made it over-complicated thereby inhibiting progress. Has anyone tried integrating Electro-magnetism into General Relativity ? I don't mean quantizing gravity and integrating it into QED version 2. No no no. It's about building a unified electro-magnetic field equation (extending Einstein Field equations). When magnetic (or electric) constant is zero (or infinity) the equation simplifies to Einstein Field equation describing how mass-energy curve space-time in the absence of Electro-magnetism (leading to General Relativity). If Gravitational constant (G) is set to zero, it describes how electro-magnetism curves space-time at large distances (e.g. charged plasma getting attracted into a highly charged spinning (macro or micro) Blackhole) leading to MGM (More General Relativity). It doesn't matter if strong and weak forces cannot be integrated into EMGM (Even More General Relativity) since they're space-time curvature is extremely short in both space and time. Scientific community needs to think outside the box of quantizing everything. MGM and QED can compare notes and figure which is more accurate even though QED is currently the best QFT ever so far in accuracy of predictions.
They are both valid two different things. Just because there's a connected field doesn't mean there isn't also a connection between radiative particles and how they interact.
Question: Why don't we consider mass itself as a consequence of the excitation of the gravitational field (space time)?
9:45 Your analogy for the string works well, Doc...Nice!
But it seems to me that you could start even farther from the string, which would serve to strengthen your analogy further. I say this because you wouldn't be able to see the string from most distances from the string, and this seems to be the starting point for String Theory (because we can't even See these extra dimensions in the regular course of our lives). And then you can just continue with your analogy as you've already done.
What do you think?
🙂
Hi @ArvinAsh. Does Roy Kerr’s work on black holes contradict general relativity? If I recall correctly, he says that singularities are not necessary in black holes
Do you have a video that talks more about why we need a graviton, i.e. a particle that mediates the "force" of gravity? My understanding is that gravity is an effect of spacetime curvature, so what does that have to do with a mediating particle?
In QFT every field is quantized and everything is described via particle creation and annihilation operators. All interactions between fields go via creation or annihilation of their quanta. When we apply this principle to Einstein's gravity field of spacetime curvature, it also becomes made of its quanta, we call them gravitons.
So matter is broken down to cells, molecules, atoms, and quarks. Atoms have 99.9 empty space, and quarks seem to flash in and out of existence . So the closer we get to sub atomic level the more we do not exist. This makes perfect sense!
Spacetime is simply empty, at all levels. It does have an additive and locally preserved system property called energy. Everything can be explained with that alone.
7:00 "we know that gravity propagates at the speed of light". This is bothersome because gravitational waves have nothing to do with light. So there must be some deeper connection between the speeds of the two types of wave. I would like to see a whole video on this subject. I think viewers would be very interested in your thoughts on this problem.
The speed of light is the speed of causality. Gravitational waves only propagate at almost the speed of light because they we free. In strongly gravitating systems gravity slows down just as much as light does.
Ok, kudos for the sneaky sponsor message, I'm not even mad.
I dont understand why gravity needs to be found in a string or particle. Why cant gravity just be an effect from mass being in space/time. Cant gravity just be space getting warped by mass? Its just the bending of space/time and not an actual thing. The thing(space/time) getting bent is something, but gravity is just whats happening, the bend and warping.
That is the problem is that we only know that gravity is the warping of space time from mass, there is an explanation or way to quantify most things in the universe and so why would gravity be an exception. Unless this universe was programmed and the code for gravity is entirely separate
Theres two local black holes that were just mapped. The magnetic fields propagating in totality in the house of mirrors averages out at focal points in the space time, producing reality. M87 and SgrA* black holes are currently eating stars that are propagating the gravity/alfven waves, along with mass attraction, and other wave forms from the universe
You are so good at this! Love your channel.
This is underselling quantum field theory. Any local (with other modest constrains) quantum theory are equivalent to a quantum field theory at low energy. In this sense, quantum field theory would always describe reality at low energy. This idea is Wilson's renormalization. This is similar to no matter what smooth function (with other modest constrains) you have, its behavior at low energy (global minimum) would always be like a 2nd degree polynomial.
The 2nd degree polynomial would always describe such functions at low energy... similar to how quantum field theory would always describe such functions at low energy.
The version of quantum field theory we have (core theory or standard model + naive gravity) can in principle already explain all daily phenomenon like biological, neuro science (and anything that is not made from billions dollars particle accelerators which is the reference for low/high energy)
How about a shout-out for Loop Quantum Gravity as an alternative?
Was the canvas of the universe wrapped up with all matter before the big bang? Or did the big bang happen upon an already existing canvas?